The Study Of Vertical Jaw Positions In Complete Denture Construction And Microprocessor-based Instrument For Dynamic Occlusal Force

Determining the Correct Vertical dimension of occlusion is one of the most important steps in making complete dentures. The study on the vertical dimension is mainly divided into two sections, the physiology of changing vertical dimension and methods for determining occlusal vertical dimension.On the basis of the Electromyographic [EMG] and clinical investigation for rest position in normal subjects with natural dentition, some investigators believed that the clinical rest position differed from the physiological rest position according to the mechanism of neuromuscular physiology. The clinical rest position is also called the mandibular postural position because it affects by body position. Some foreign authors have described the ralation between the muscular electrical activity and the vertical dimension in the natural dentition, but no studies have been reported on EMG activity of masticatory muscles varing vertical dimension for edentulous patients, maintaining constant bite force.Many methods are used for determining vertical dimension of occlusion in edentulous patients such as pre-extraction records, maximum bite force, patient's judgement with many trials, phonetics, swallowing, cephalometric radio-graphs, facial measurement and determining mandibular posture position. One of the common clinically methods is that tne vertical dimension of occlusion is determined by subtracting the interocclusal space from the mesure-ment of vertical dimension of the mandibular posture position.An interocclusal space is absolutely essential for natural dentitions or artificial dentitions. The results of numerous measurement showed that normal interocclusal space is an average 1 to 4mm. However, it has not been reported that is there an optimal physiological range of the interocclusal space for edentulous patients individual?Masticatory function is one of main functions for stomatognathic system. EMG, occlusal force, i.e bite force and chewing force, and chewing efficiency are three important methods which are often discussed in the evaluation of the fanctional condition of the masticatory system and applied on the prosthetic fields. The purpose of the present experimental work is to study the relation between EMG, bite force, chewing force, chewing efficiency and the occlusal...